Texas state police will form an “internal committee” to review the response by state law enforcement to the May primary school mass shooting in Uvalde, after a legislators’ investigation blamed “systemic failures” and poor leadership.

The report released on Sunday of the Texas House of Representatives committee investigation marked the most exhaustive attempt so far to determine why it took more than an hour for police and other officers to confront and kill the 18-year-old gunman at Robb Elementary School on May 24.

Nineteen children and two teachers were killed in the massacre.

The White House called the report “devastating” and “unacceptable”.

The Texas Department of Public Safety said on Monday it had formed “an internal committee for the inquiry”.

It will also determine “where the department can make necessary improvements for future mass casualty responses”, according to a department statement.

The Texas DPS said its review will “determine if any violations of policy, law, or doctrine occurred” during the response.

It was not clear whether disciplinary action would be taken after either of the investigations’ outcomes.

The report, released on Sunday, found “law enforcement responders failed to adhere to their active shooter training, and they failed to prioritise saving the lives of innocent victims over their own safety”.

The 77-page report said 376 law enforcement officers rushed to the school in a chaotic scene marked by a lack of clear leadership and sufficient urgency.

The report’s findings put more than 90 state troopers at the school during the shooting.

The report also found that of the approximately 142 rounds the attacker fired inside the building, it was “almost certain” about 100 were fired before any officer entered the school.

Law enforcement officials have been roundly criticised by the victims’ family members, state legislators and the general public for their handling of the rampage.

State police officials have in turn called out the leadership of Pete Arredondo, the police chief of the school district’s six-man police force, who they have said was in control of the scene.

But the report noted hundreds of officers from agencies that were better trained and better equipped than the school police force badly failed, too.

The US Justice Department has said it will review the law enforcement response in Uvalde and will make its findings public.

-AAP